// 念のためapt-getをupdate && upgrade
$ apt-get update
$ apt-get upgrade

// MariaDBのインストール
$ apt-get install mariadb-server

// MariaDBがインストールされたことの確認
// /etc配下にmysqlフォルダがある
$ cd /etc
$ cd ls

$ mysql_secure_installation
NOTE: RUNNING ALL PARTS OF THIS SCRIPT IS RECOMMENDED FOR ALL MariaDB
      SERVERS IN PRODUCTION USE!  PLEASE READ EACH STEP CAREFULLY!

In order to log into MariaDB to secure it, we‘ll need the current
password for the root user.  If you‘ve just installed MariaDB, and
you haven‘t set the root password yet, the password will be blank,
so you should just press enter here.

// rootユーザのパスワードを設定しましょう！
Enter current password for root (enter for none):
OK, successfully used password, moving on...

Setting the root password ensures that nobody can log into the MariaDB
root user without the proper authorisation.

You already have a root password set, so you can safely answer 'n'.

// rootユーザのパスワードを変更しますか？(既に設定したので "n" を入力)
Change the root password? [Y/n] n
 ... skipping.

By default, a MariaDB installation has an anonymous user, allowing anyone
to log into MariaDB without having to have a user account created for
them.  This is intended only for testing, and to make the installation
go a bit smoother.  You should remove them before moving into a
production environment.

// 匿名ユーザを削除しますか？
Remove anonymous users? [Y/n] y
 ... Success!

Normally, root should only be allowed to connect from 'localhost'.  This
ensures that someone cannot guess at the root password from the network.

// リモートでrootによるログインを許可しますか？
Disallow root login remotely? [Y/n] y
 ... Success!

By default, MariaDB comes with a database named 'test' that anyone can
access.  This is also intended only for testing, and should be removed
before moving into a production environment.

// test用のデータベースを削除しますか？
Remove test database and access to it? [Y/n] y
 - Dropping test database...
 ... Success!
 - Removing privileges on test database...
 ... Success!

Reloading the privilege tables will ensure that all changes made so far
will take effect immediately.

// テーブルへの特権情報をリロードしますか？(上記までの変更を即時反映させるため "y" を選択)
Reload privilege tables now? [Y/n] y
 ... Success!

Cleaning up...

All done!  If you‘ve completed all of the above steps, your MariaDB
installation should now be secure.

Thanks for using MariaDB!

// MariaDBにログイン
$ mysql -u root -p
// ユーザを作成
MariaDB [(none)]> create user 'takahiro'@'localhost' identified by 'password';
// ユーザの一覧を確認
MariaDB [(none)]> select Host, User, Password from mysql.user;
+-----------+----------+-------------------------------------------+
| Host      | User     | Password                                  |
+-----------+----------+-------------------------------------------+
| localhost | root     |                                           |
| localhost | takahiro | ***************************************** |
+-----------+----------+-------------------------------------------+

mysql
├── conf.d
│    ├── mysql.cnf
│    └── mysqldump.cnf
├── debian-start
├── debian.cnf
├── mariadb.cnf
├── mariadb.conf.d
│    ├── 50-client.cnf
│    ├── 50-mysql-clients.cnf
│    ├── 50-mysqld_safe.cnf
│    └── 50-server.cnf
├── my.cnf
└── my.cnf.fallback

# The MariaDB configuration file
#
# The MariaDB/MySQL tools read configuration files in the following order:
# 1. "/etc/mysql/mariadb.cnf" (this file) to set global defaults,
# 2. "/etc/mysql/conf.d/*.cnf" to set global options.
# 3. "/etc/mysql/mariadb.conf.d/*.cnf" to set MariaDB-only options.
# 4. "~/.my.cnf" to set user-specific options.
#
# If the same option is defined multiple times, the last one will apply.
#
# One can use all long options that the program supports.
# Run program with --help to get a list of available options and with
# --print-defaults to see which it would actually understand and use.

#
# This group is read both both by the client and the server
# use it for options that affect everything
#
[client-server]

# Import all .cnf files from configuration directory
!includedir /etc/mysql/conf.d/
!includedir /etc/mysql/mariadb.conf.d/

[mysql]

[mysqldump]
quick
quote-names
max_allowed_packet      = 16M

#
# This group is read by the client library
# Use it for options that affect all clients, but not the server
#

[client]
# Default is Latin1, if you need UTF-8 set this (also in server section)
default-character-set = utf8mb4

# This group is *never* read by mysql client library, though this
# /etc/mysql/mariadb.cnf.d/client.cnf file is not read by Oracle MySQL
# client anyway.
# If you use the same .cnf file for MySQL and MariaDB,
# use it for MariaDB-only client options
[client-mariadb]

#
# These groups are read by MariaDB command-line tools
# Use it for options that affect only one utility
#

[mysql]
# Default is Latin1, if you need UTF-8 set this (also in server section)
default-character-set = utf8mb4

[mysql_upgrade]

[mysqladmin]

[mysqlbinlog]

[mysqlcheck]

[mysqldump]

[mysqlimport]

[mysqlshow]

[mysqlslap]

[mysqld_safe]
# This will be passed to all mysql clients
# It has been reported that passwords should be enclosed with ticks/quotes
# escpecially if they contain "#" chars...
# Remember to edit /etc/mysql/debian.cnf when changing the socket location.
socket          = /var/run/mysqld/mysqld.sock
nice            = 0
skip_log_error
syslog

#
# These groups are read by MariaDB server.
# Use it for options that only the server (but not clients) should see
#
# See the examples of server my.cnf files in /usr/share/mysql/
#

# this is read by the standalone daemon and embedded servers
[server]

# this is only for the mysqld standalone daemon
[mysqld]

#
# * Basic Settings
#
user            = mysql
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
port            = 3306
basedir         = /usr
datadir         = /var/lib/mysql
tmpdir          = /tmp
lc-messages-dir = /usr/share/mysql
skip-external-locking

# Instead of skip-networking the default is now to listen only on
# localhost which is more compatible and is not less secure.
bind-address            = 127.0.0.1

#
# * Fine Tuning
#
key_buffer_size         = 16M
max_allowed_packet      = 16M
thread_stack            = 192K
thread_cache_size       = 8
# This replaces the startup script and checks MyISAM tables if needed
# the first time they are touched
myisam-recover         = BACKUP
#max_connections        = 100
#table_cache            = 64
#thread_concurrency     = 10

#
# * Query Cache Configuration
#
query_cache_limit       = 1M
query_cache_size        = 16M

#
# * Logging and Replication
#
# Both location gets rotated by the cronjob.
# Be aware that this log type is a performance killer.
# As of 5.1 you can enable the log at runtime!
#general_log_file        = /var/log/mysql/mysql.log
#general_log             = 1
#
# Error log - should be very few entries.
#
log_error = /var/log/mysql/error.log
#
# Enable the slow query log to see queries with especially long duration
#slow_query_log_file    = /var/log/mysql/mariadb-slow.log
#long_query_time = 10
#log_slow_rate_limit    = 1000
#log_slow_verbosity     = query_plan
#log-queries-not-using-indexes
#
# The following can be used as easy to replay backup logs or for replication.
# note: if you are setting up a replication slave, see README.Debian about
#       other settings you may need to change.
#server-id              = 1
#log_bin                        = /var/log/mysql/mysql-bin.log
expire_logs_days        = 10
max_binlog_size   = 100M
#binlog_do_db           = include_database_name
#binlog_ignore_db       = include_database_name

#
# * InnoDB
#
# InnoDB is enabled by default with a 10MB datafile in /var/lib/mysql/.
# Read the manual for more InnoDB related options. There are many!

#
# * Security Features
#
# Read the manual, too, if you want chroot!
# chroot = /var/lib/mysql/
#
# For generating SSL certificates I recommend the OpenSSL GUI "tinyca".
#
# ssl-ca=/etc/mysql/cacert.pem
# ssl-cert=/etc/mysql/server-cert.pem
# ssl-key=/etc/mysql/server-key.pem

#
# * Character sets
#
# MySQL/MariaDB default is Latin1, but in Debian we rather default to the full
# utf8 4-byte character set. See also client.cnf
#
character-set-server  = utf8mb4
collation-server      = utf8mb4_general_ci

#
# * Unix socket authentication plugin is built-in since 10.0.22-6
#
# Needed so the root database user can authenticate without a password but
# only when running as the unix root user.
#
# Also available for other users if required.
# See https://mariadb.com/kb/en/unix_socket-authentication-plugin/

# this is only for embedded server
[embedded]

# This group is only read by MariaDB servers, not by MySQL.
# If you use the same .cnf file for MySQL and MariaDB,
# you can put MariaDB-only options here
[mariadb]

# This group is only read by MariaDB-10.0 servers.
# If you use the same .cnf file for MariaDB of different versions,
# use this group for options that older servers don‘t understand
[mariadb-10.0]